## surface excess isotherm

https://doi.org/10.1351/goldbook.S06178
The function relating, at constant temperature and pressure, $$\mathit{\Gamma}_{i}^{\left(\text{n}\right)}$$, $$\mathit{\Gamma}_{i}^{\left(\text{l}\right)}$$ or $$\mathit{\Gamma}_{i}^{\left(\text{v}\right)}$$, or the respective specific quantities $$\frac{n^{\text{l}}\ \Delta x_{i}^{\text{l}}}{m}$$, $$\frac{A_{\text{s}}\ \mathit{\Gamma }_{i}^{\left(\text{l}\right)}}{m}$$ or $$\frac{V^{\text{l}}\ \Delta c_{i}^{\text{l}}}{m}$$ to the @[email protected] (or concentration) of component $$i$$ in the equilibrium liquid phase. With solutions of more than two components such isotherms are unequivocal functions only when the ratios of the @[email protected] fractions (or concentrations) of all other components except $$i$$ are kept constant. ($$A_{\text{s}}$$ is the @[email protected], $$\mathit{\Gamma}_{i}^{\left(\text{n}\right)}$$, $$\mathit{\Gamma}_{i}^{\left(\text{l}\right)}$$, $$\mathit{\Gamma}_{i}^{\left(\text{v}\right)}$$ are relative adsorptions, $$\Delta x_{i}^{\text{l}}$$ is the change in @[email protected] of $$i$$ resulting from bringing a specified mass $$m$$ of solid into contact with a specified amount of solution $$n^{\text{l}}$$, $$\Delta c_{i}^{\text{l}}$$ is the change in concentration resulting from bringing a specified mass of solid into contact with a specified amount of solution of volume $$V^{\text{l}}$$.)
Source:
PAC, 1972, 31, 577. (Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry) on page 593 [Terms] [Paper]